T72 Flyby |
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T72 Flyby |
 Sep 28 2010, 02:58 PM
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#16
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Rover Driver  Group: Members Posts: 977 Joined: 4-March 04 Member No.: 47  |
mmm perhaps a bit like the v-shaped markings on Venus
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Sep 28 2010, 04:38 PM
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#17
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Member Group: Members Posts: 474 Joined: 1-April 08 From: Minnesota ! Member No.: 4081 |
The zonal atmospheric flow pattern may be different at this time of the equinox. According to Friedson et al http://www.sciencedirect.com/science?_ob=M...=/sdarticle.pdf atmospheric flow rises at low latitudes, flows towards the poles and descends at higher latitudes. Could we be seeing this pattern in the clouds?
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Sep 28 2010, 04:45 PM
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#18
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 Senior Member Group: Members Posts: 3534 Joined: 1-October 05 From: Croatia Member No.: 523 |
Here's a ratio image of a stack of flatfielded and unsharped CB3 frames and an MT1 frame to roughly remove the effects of illumination.
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Sep 28 2010, 04:51 PM
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#19
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 Senior Member Group: Moderator Posts: 2605 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Thanks Gordan. I had suspected that there were two small thin clouds near the arrowhead shaped bright terrain at center left. This image seems to confirm that.
Dunno if they are associated with the main "cloud feature" or not. -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Sep 28 2010, 06:33 PM
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#20
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 Senior Member Group: Members Posts: 2929 Joined: 4-November 05 From: North Wales Member No.: 542 |
It would be interesting to see that reprojected to simulate the view from directly above.
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Sep 28 2010, 06:34 PM
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#21
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 Administrator Group: Chairman Posts: 13226 Joined: 8-February 04 Member No.: 1 |
It would be incredibly distorted being so close to the edge.
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Sep 28 2010, 06:37 PM
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#22
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Senior Member Group: Members Posts: 3534 Joined: 1-October 05 From: Croatia Member No.: 523 |
A reprojected view so close to the limb would only be accurate if the cloud feature was very close to the ground. I'm not entirely sure that's a safe assumption to make.
Edit: snap! beat me to the punch. -------------------- |
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Sep 28 2010, 07:03 PM
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#23
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Senior Member Group: Members Posts: 2929 Joined: 4-November 05 From: North Wales Member No.: 542 |
Agreed, differences in elevation could distort the result. I only proposed the idea because previous posts suggest it's confined to the troposphere, i.e. no higher than 40 km or so, and because it's clearly so large in horizontal extent. Also, if it's the spreading top of a giant convection cell or cluster thereof I think there's a good chance that the upper surface of the cloud is reasonably level. I still hope somebody has a go at the reprojection. It would at least facilitate comparison with Earth-based observations of previous events missed by Cassini.
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Sep 28 2010, 10:07 PM
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#24
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Senior Member Group: Members Posts: 2929 Joined: 4-November 05 From: North Wales Member No.: 542 |
Some further thoughts - -
All previous cloud patches observed by Cassini have been groupings of latitudinal streaks, but this one at first sight doesn't look like that. It may be that this cloud patch is the same, but the circumstances of viewing make it look different, or it may really be different. Let's suppose the latter. What could account for this? Perhaps we are seeing different stages of the same phenomenon. The cloud forms in some random and sudden way in which no particular direction is favoured, leaving an 'ink blot' which is then sliced into latidudinal streaks during calmer times. This one is just fresher than the others observed so far. . . . ??? |
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Sep 28 2010, 11:40 PM
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#25
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Member Group: Members Posts: 474 Joined: 1-April 08 From: Minnesota ! Member No.: 4081 |
The extent of this cloud and its shape seems unique compared to what we've seen from Cassini's cameras so far. Still it may be very similar to the event of April 2008 where tropical storm clouds were documented via ground based observatories (NASA infrared telescope facility initially). It would be interesting to learn if this event is right now under observation from the Gemini North observatory!!
The animation below depicts the extent of the cloud on the Titan planetary grid. ??? have all the Sept 27 raw images come down ?
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Sep 29 2010, 12:27 AM
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#26
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Member Group: Members Posts: 567 Joined: 4-September 06 From: Boston Member No.: 1102 |
I know a bunch of hard core planetary climate scientists have seen these images and are going wow!!! I think they could post their gut responses without jeopardizing their Science or Nature articles...
 -------------------- Floyd
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Sep 29 2010, 01:13 AM
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#27
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 Member Group: Members Posts: 713 Joined: 29-December 05 From: NE Oh, USA Member No.: 627 |
Wow!
Craig |
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Sep 29 2010, 01:48 AM
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#28
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 Senior Member Group: Moderator Posts: 6474 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Indeed!
Gonna be fascinating to hear the pros' take on this thing. By any chance, were any ground-based observatories taking albedo measurements of Titan shortly before T72? Would be useful to constrain how much time this feature had to develop. -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Sep 29 2010, 02:54 AM
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#29
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Senior Member Group: Moderator Posts: 2605 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Yup. They noticed. cpcomments e-mail went out 8:30 PM today from Carolyn Porco. From message:
"Just down on the ground today: Images of some of the largest clouds our cameras on Cassini have yet seen on Titan! And the fact that we see them in the equatorial region is big news and may signify seasonal change is underway!" http://www.ciclops.org/view_event/142/TITA...138_RAW_PREVIEW -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Sep 29 2010, 06:21 AM
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#30
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Member Group: Members Posts: 474 Joined: 1-April 08 From: Minnesota ! Member No.: 4081 |
QUOTE (nprev @ Sep 28 2010, 08:48 PM)  Indeed! Gonna be fascinating to hear the pros' take on this thing. By any chance, were any ground-based observatories taking albedo measurements of Titan shortly before T72? Would be useful to constrain how much time this feature had to develop. We had good views of Senkyo from the 13 of September and there were no obvious clouds at that time. Still, plenty of time for something to develop after that however. 
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